Assembly for picking and transporting nanoobjects contained in aerosols, with a cassette the opening of which is secured during the picking

ABSTRACT

An assembly for picking and transporting nano-objects, comprises a cassette having first and second components, which are provided with means of mutual assembly and with means for holding the filter. The first and second components define, when the components are in an assembled configuration, a cavity in which the filter is housed and held therein. The means of mutual assembly comprise first clipping means secured to the first component, second clipping means secured to the second component and able to collaborate with the first clipping means so as to clip the two components together. A picking device comprises suction means to which the cassette is able to be removably attached. The first and second clipping means are configured such that they are not accessible from the outside when the components are in the assembled configuration with the cassette fixed to the device.

This application is a national stage application of International PCTApplication No. PCT/IB2015/054209, filed internationally on Jun. 3,2015, which claims priority to French Application No. FR 14 55051, filedJun. 4, 2014, the entire content of each of which is incorporated byreference herein in its entirety.

TECHNICAL FIELD

The present invention concerns the field of collection and analysis ofnanoparticles susceptible of being present in suspension in the air.

More particularly, it concerns the design of an assembly for samplingand transporting of nano-objects contained in aerosols, with a samplingcassette. The present invention proposes to improve the securing of theopening of such a cassette in order to guarantee the integrity of thesampling.

PRIOR ART

The rapid rise of nanotechnologies is making it necessary to look intothe health and environmental impacts of these new materials in order tohave optimal safety conditions. For several years, nanoparticles, orparticles with nanometer dimensions, have been the subject of intenseresearch and their use has begun to spread into various fields such ashealth, microelectronics, energy technologies or ordinary consumerproducts such as paints and cosmetics. It is therefore necessary tocreate methods for evaluation and monitoring of the exposure of workers,consumers and the environment to nanoparticles.

The development of reliable methods of sampling and analysis of aerosolsis thus a crucial issue in terms of public health and prevention ofrisks at workstations. In particular, the development of samplingdevices adapted to be portable and secured as a unit to the work clothesof a worker at a station for the manufacture of nano-objects or theprocessing of nano-materials might prove to be mandatory.

The method of choice for sampling, or the one which is preferred atpresent, consists in aspirating a flow of air liable to be laden withparticles through a filter which is then analyzed by various techniques(gravimetry, microscopy, XRF, etc.).

In the prior art, sampling devices also known as cassette samplers arealready known, these being portable and having to sample an aerosolcontamination liable to be inhaled through the mouth and the nose of anindividual during his respiration.

A sampler is a device which comprises in particular means of aspirationand on which is secured, generally in removable manner, a samplingcassette holding at least one filter for sampling of contaminants byaspiration.

Thus, the U.S. Pat. No. 4,961,916 concerns a sampling device for gaseousand particulate pollutants comprising a cassette inside which threefilters are stacked one on top of the other and comprising two openingson either side of these filters, one of them emerging into the outsideenvironment liable to be polluted and the other one emptying into a pipeconnected to a suction pump. Thus, from upstream to downstream, duringthe aspiration by the pump, the first filter enables collecting of onlythe particulate fraction of the aerosol, the second filter, previouslyimpregnated with a reagent, enables a selective reaction with one ormore gaseous compounds, and the third filter only has the function ofstiffening the filter assembly. The sampling with which this patent isconcerned is the collection of gaseous and particulate isocyanates whichare present in polluted air.

The U.S. Pat. No. 5,205,155 for its part discloses a sampling device forasbestos fibers liable to be in suspension in the air and its concern isthe nonuniform deposition on the filter housed in the sampling cassette.As a remedy, the patent proposes designing the inlet of the cassette,that is, the one near the aspiration orifice of the particularenvironment, in a flared shape and making it smooth so as to promote ahomogeneous deposition of particles on the filter.

Patent application US 2008/0196514A1 concerns an individual samplingdevice for dust, used to collect the inhalable fraction of airborneparticles. This patent describes various shape ratios of the cassette(ratios between length L and inlet diameter D of the opening) which,according to it, allow an improvement in the sampling by aspiration.What is more, this patent mentions that, for the most representativenature of the inhalation through the nose, it is advantageous to providea vertical orientation of the air flow aspirated from bottom to top.

Patent application US 2009/0272202A1 concerns an individual samplingdevice for nanoparticles comprising a cassette with different stages ofselection of particles depending on their size. The disclosed devicecomprises an assembly bringing together the different stages withassembly plates held together by springs and guide rods used forguidance during the assembly process.

All the methods and devices for sampling of aerosols in the prior art,as described, have one or more major drawbacks, which can be summarizedas follows:

-   -   the majority of the sampling methods for aerosols require an        extraction of the filter from its cassette in situ, that is, at        the place of the sampling. The implementing devices are thus        designed for the cassette to be opened easily and by anyone at        all: thus, an opening with untimely extraction may result in        contamination external to the filter, in a loss of material        adsorbed onto the filter or in a poor traceability of the        filter. In particular, a worker at a manufacturing station for        nano-objects or processing of nano-materials may open a cassette        in untimely manner, contaminate a filter, put back a filter        already used, etc.    -   all the cassettes in sampling configuration, that is, a        configuration secured to the sampling device (sampler), can        still be opened by the worker, because they are accessible from        all parts. This does not allow a sampler to be left unattended        with groups of workers not authorized for its opening, without        the certainty that the cassette has not been disassembled and        thus that the analysis of the sample/the sampling is afterwards        invalidated.

The inventors of the present application have proposed, in patentapplication FR 2981154, a two-piece sampling cassette, the pieces ofwhich are assembled by clipping means not accessible from the outside.Thus, these clipping means can only be physically accessed through pinsindividually lodged in holes, but this cannot be done manually or byusing just any tool from the space from outside the cassette in theconfiguration with the two pieces assembled together. Thanks to theclipping means, the cassette is thus secured, since it cannot be openedin untimely manner, as its opening for the actual analysis of the samplerequires an adequate tool to separate the two pieces of the cassette.

While this securing of the opening of the cassette is perfectly adequatein the majority of situations, the inventors nevertheless determinedthat there still existed a situation of untimely opening, in the casewhen an unauthorized person might have pins for disassembling the twopieces of the cassette from each other. In other words, there stillexists a risk of opening of the sampling cassette according toapplication FR 2981154, even though this risk is minimal.

The general purpose of the invention is thus to mitigate some or all ofthe drawbacks of the prior art and especially to improve the cassetteaccording to patent application FR2981154, and thus to propose asolution which guarantees the integrity of the sampling accomplished bya device for sampling and transporting of nano-objects liable to bepresent in an aerosol and to make sure of the traceability of thesampling up to the point of the elemental analysis proper, even in asituation where an unauthorized person might have adequate means for theopening of the cassette of the device in the assembled configuration.

It will be noted that elemental analysis is an analysis able todetermine which atomic elements (titanium, carbon, nickel, etc.) arepresent, as well as their atomic percentage in the sample. On the otherhand, an elemental analysis is not able to determine the structure orhow these elements are assembled with one another.

One particular purpose of the invention is to propose a device of thiskind which is simple to produce and low in cost.

EXPLANATION OF THE INVENTION:

To accomplish this, the invention first of all involves an assembly forsampling and transporting nano-objects liable to be present in anaerosol for the purposes of their analysis, comprising:

-   -   a device comprising a porous sampling filter able to trap        nano-objects liable to be in suspension in the aerosol, a        cassette composed of a first piece and a second piece provided        with means of mutual assembly and means of holding the filter,        the first and second pieces in their assembled configuration        defining a cavity in which the filter is lodged while being        held, and at least one gasket able to produce tightness between        the cavity and the outside, the means of mutual assembly        comprising first clipping means integrated with the first piece,        second clipping means integrated with the second piece and able        to cooperate with the first means in order to bring about a        clipping of the two pieces;    -   a sampling apparatus comprising means of aspiration and a seat        in which the cassette can be secured in a removable manner when        the two pieces are in the assembled configuration to accomplish        the sampling of the contaminants by means of aspiration.

According to the invention, the arrangement of the edges of the seat forfixation of the cassette relative to the clipping means is such thatthey cannot be reached physically, either manually or by a tool, evenone adapted to their unclipping, in the assembled configuration of thepieces, when the cassette is in its configuration secured to theapparatus.

The phrase “not be accessible from the outside” means that the clippingmeans cannot be reached physically, either manually or by using anunclipping tool for the means of clipping of the pieces of the cassettefrom the space outside the device in the assembled configuration of thecassette, when it is in its configuration secured to the apparatus.

Thus, as compared to the sampling cassette according to patentapplication FR 2981154, the securing of the opening of the cassette isimproved, since when it is secured to the apparatus even a tool adaptedto unclipping the means of clipping of the pieces cannot physicallyreach these means.

The securing of the opening of the cassette according to the inventionmakes it possible to limit the risks of contamination of the filter. Thesources of contamination can be classified into three categories, whichcan be enumerated as follows:

-   -   a later contamination which might artificially increase the        quantity of particles on the cassette (deposition),    -   a decrease in the quantity of particles sampled on the filter        (scraping);    -   a pollution of a kind different than the one being sampled.

Moreover, the risk of contamination of the filter, the opening of thecassette by an unauthorized user, might result in an unfortunateexchanging of filters corresponding to different workers which wouldresult in a wrong match-up of worker and filter and thus lead to a wrongmonitoring of the exposure of the worker at his workstation. This breakin the chain of traceability would compromise the monitoring of theexposure of the workers to nano-materials.

The invention makes it possible to strengthen this securing of thesampling: once inserted into its fixation seat on the apparatus, thecassette no longer allows the use of the tool to open it. The cassettefirst needs to be extracted from its seat. Thus, an unauthorized userwho is nonetheless tempted to open the cassette would be forced toremove it from the apparatus to which it is secured. One may arrangethat this will have the immediate consequence of halting the means ofaspiration of the apparatus. Moreover, an appropriate detection systemintegrated in the apparatus, such as a sound and/or visual alarm, thenallows a detecting of the unwanted removal of the cassette, and theninterrupting of the sampling. Moreover, a registration of thisinterruption can then be done.

The solution according to the invention makes it possible to increasethe compactness and robustness of the sampling cassette, of theproduction tooling for the cassette, as well as of the opening tool ofthe cassette, and allows their cost to be decreased. The reduction insize of the cassette is advantageous both from a standpoint ofergonomics and from one of handling or storage. The gain in terms ofmaterial cost is linked to the fact that a cassette according to theinvention is more compact than a cassette according to patentapplication FR 2981154. This compactness implies a cost for the toolingto manufacture the cassette (injection molds) that is also lower thanthat of a cassette according to patent application FR 2981154.

The invention likewise deals with a sampling device for the assemblydescribed above, wherein the means of holding the filter comprise twoshoulders, one produced on an internal periphery of the first piece andthe other on an internal periphery of the second piece, the devicecomprising a filter holder held by squeezing between the two shoulders.

According to one advantageous variant, at least one of the piecescomprises a notch running straight through the annular rim, the filterholder comprises a tongue that is complementary to the notch (ornotches) and to which an identification element of the filter issecured, such that in the assembled configuration of the pieces and inthe configuration of the cassette secured to the apparatus theidentification element is in contact with the outer environment.

The phrase “in contact with the outer environment” means that theidentification element energes into the space outside the device and theapparatus in the assembled configuration of the cassette when it issecured to the apparatus.

The identification element is preferably an electronic chip or aradiofrequency ID tag (RFID) or a two-dimensional barcode, of theDatamatrix® type. It may be secured by a gluing technique, by engraving,by overmolding or by tampography. The identification element may also besimply numbers and/or letters in order to be visible and read directlyby a person.

In cumulative or alternative manner, one can provide an identificationelement of the filter constituted by at least one radiofrequency ID tag(RFID), the RFID tab(s) being lodged in the first and/or in the secondpiece. Preferably, the RFID tag can be lodged in the lower piece of thecassette. This variant has the advantage of preserving identification onthe filter itself, and of being able to subject the filter to analyseswhich might alter the electronic circuit of a RFID tag. Specifically, bylodging a RFID tag in one and/or the other pieces of the cassette, thereare no longer any electronics integrated directly in the filter and thefilter holder, and thus an analysis undergone by the filter does notdisrupt the electronic circuit of the tag. This also has the advantageof allowing the RFID chip to be brought closer to the sampling apparatusand thus of the transmission power of its antenna being reduced.

Preferably, the filter holder is deformable by compression in order tobe flattened by the first and second pieces in the assembledconfiguration and thus form a single gasket.

One can provide at least one elastomer seal bearing against at least oneof the shoulders.

The filter can be made of membranes made of alumina; silica, quartz orborosilicate fibers; cellulose or its derivatives such asmethylcellulose (MCE); polyvinylidene fluoride (PVDF); polyestersulfone(PES); polystyrene (PS); polytetrafluoroethylene (PTFE); polycarbonate(PC). Generally, it is several micrometers to several tens ofmicrometers thick, for example, 10 to 200 micrometers. Typically, thefilters have a thickness between 5 and 30 μm.

Advantageously, the first and second pieces and the filter holder arebased on thermoplastic material, preferably polyethylene terephthalate(PET), polybutylene terephthalate (PBT), polymethyl methacrylate (PMMA),polyamide 6 (PA6), polyamide 66 (PA66), polycarbonate (PC),polypropylene (PP) or polyoxymethylene copolymer (POM-C).

According to one advantageous embodiment, the first clipping means areformed by a number equal to n of elastically deformable feet whose endcomprises an opening and which are arranged on the first piece, beingspaced apart by an angular position equal to it 2π/n, and in that thesecond clipping means are formed by a same number n of protrusions ofcomplementary shape to the openings and arranged on the second piece,being spaced apart by the same angular position equal to it 2π/n as thefeet.

The invention further deals with a tool designed to perform theunclipping of the two pieces of the cassette, comprising pins which arespaced apart from each other by the same position as the protrusions andable to exert a thrusting on the latter, laterally to the longitudinalaxis of the cassette.

The tool can further comprise means of mechanical guiding able to guidethe tool underneath the piece provided with protrusions in order tofacilitate the simultaneous lateral thrusting of the pins against theprotrusions.

Finally, the invention deals with the use of an assembly as describedabove as an assembly for monitoring the exposure of workers at amanufacturing station for nano-objects, processing of nano-materials, oruse of products containing them.

DETAILED DESCRIPTION

Other advantages and features will emerge more clearly from a perusal ofthe following detailed description, given as an illustration but notlimited by this, making reference to the following figures, in which:

FIG. 1 is a profile view of the sampling cassette of a sampling deviceaccording to the invention, the cassette being in the assembledconfiguration,

FIG. 1A is a bottom view of the cassette of FIG. 1;

FIG. 2 is an exploded perspective view of the cassette of FIGS. 1 and 1Ashowing the two pieces of the cassette in non-assembled configuration;

FIG. 3 is a sectional view of the cassette of FIGS. 1 to 2, furthershowing a tool according to the invention for the secured opening of thecassette;

FIG. 4 is a perspective view showing a sampling assembly according tothe invention with an apparatus integrating an aspiration pump and acassette according to FIGS. 1 to 2 in a configuration secured to theapparatus;

FIG. 4A is a detail sectional view of FIG. 4;

FIG. 5 is a bottom view of the cassette of FIG. 1 showing one variantfor the integration of a RFID identification tag;

FIGS. 6 and 7 are respectively perspective and top views of the cassetteaccording to FIGS. 1 to 2 mounted in its opening tool of its pieces;

FIGS. 8 and 9 are sectional views of FIG. 7 along A-A, respectivelybefore and after opening of the pieces of the cassette.

In order to carry out a sampling of nano-objects liable to be containedin an aerosol, the device according to the invention comprises first ofall a filter, not shown, which is adapted to trap nano-objects liable tobe in suspension in air, which is lodged and held in a cavity formed bya cassette in the closed configuration.

Thus, the sampling method according to the invention consists inorienting the closed cassette so that the air being analyzed isaspirated by a pump, not shown, which is integrated in a samplingapparatus 6 to which the cassette is attached, the air being aspiratedfrom an orifice 20 and emerging from the cassette through an orifice 10and then going to the pump.

The aspiration can of course be provided along a reverse path, that is,from the orifice 10 to the orifice 20. The nano-objects or particles ofmicrometer size so aspirated will be collected on the filter held in thecassette. In the method of sampling according to the invention, thecassette is oriented so that the sampling is as representative aspossible of the respiration by being located less than 30 cm from therespiratory passages.

As is represented, the device according to the invention allowscollecting of a sample and the transporting of the trapped nano-objectsin a secured manner with perfect traceability.

The assembly for sampling and transporting of nano-objects according tothe invention thus comprises the device with cassette and filter and thesampling apparatus 6 to which the cassette is secured during thesampling and which integrates the aspiration pump.

As is illustrated in FIGS. 1 to 2, the cassette is composed of twopieces 1, 2 of general cylindrical shape.

The upper piece 2 is provided with feet 21 which are flexible, in otherwords elastically deformable, whose end comprises an opening 210.

The lower piece 1 is provided with cavities (or “channels”) 11 which areindividually complementary to a foot 21 with one end comprising aprotrusion individually complementary to an opening 210. Of course, inthe scope of the invention one can provide an arrangement of thecomplementary openings or protrusions in the reverse manner, that is,with protrusions individually in a cavity of the piece 2 and feet withopenings on the piece 1.

The relative angular arrangement between flexible feet 21 of the upperpiece 2 is identical to that of the cavities 11 of the lower piece 1.

Thus, in the mutual assembled configuration, the feet 21 with theiropenings 210 fit into and are clipped precisely in the cavities 11 andaround the protrusions 110 (FIGS. 1A and 2).

FIGS. 4 and 4A show the cassette with the pieces 1, 2 assembledtogether, such that it is secured to the sampling apparatus 6integrating the aspiration pump for the contaminants.

As can be seen in these FIGS. 4 and 4A, in this mutually assembledconfiguration of the pieces 1, 2 and with the cassette secured to theapparatus 6, no clipping means 11, 110, 21, 210 is accessible from theoutside, even with an adequate tool 5 as described hereafter enables theremoval of the two pieces 1, 2. In other words, the arrangement of theedges of the seat for fixation 60 of the cassette relative to theclipping means is such that they cannot be reached physically, eithermanually or by a tool adapted to their unclipping.

Thanks to the invention, any untimely opening of the cassette outside ofthe analysis laboratory designated to analyze precisely the particlestrapped on the filter is prevented.

Thus, as compared to the cassette according to patent application FR2981154, the securing of the sampling is strengthened because thecassette once inserted in its fixation seat 60 on the apparatus does noteven allow the use of the unclipping tool for the opening of the latter.The cassette first needs to be extracted from its seat. Thus, anunauthorized user who was nonetheless tempted to open the cassette wouldneed to remove it from the apparatus to which it is secured. One mayprovide that this will have the immediate consequence of halting themeans of aspiration of the apparatus. Moreover, an appropriate system ofdetection integrated in the apparatus, such as a sound and/or visualalarm, then allows for a detecting of the unwanted removal of thecassette, and an interrupting of the sampling process. Furthermore, aregistration of this interruption can then be done.

One thus limits the risks of contamination of the latter, these notactually being representative of the sampling process and possiblyoccurring either due to decrease in the number of particles trapped onthe filter (scraping) or adding of particles of a different nature thanthose being sampled.

As is better shown in FIG. 4A, in the configuration of the cassette 1, 2secured to the sampling apparatus 6, the orifice 10 of the lower piece 1of the cassette is in tight fluidic communication with the aspirationorifice 61 provided in the body of the sampling apparatus 6.

The lower piece 1 is provided with holes 13 emerging at the same time onthe outside and in the zone where the protrusions 110 are arranged, thatis, in the area of the zone where protrusions 110 cooperate by clippingwith the feet 21 with their corresponding openings 210. There aretherefore as many holes 13 as there are complementary clipping means.

The upper piece 2 has three flexible feet 21, positioned at 120°relative to each other, which fit precisely into the cavities 11 of thelower piece 1.

Once the sampling has been performed, the pump of the apparatus ishalted and then the cassette is removed from its fixation seat 60 of theapparatus and then the sampling cassette is opened, that is, theunclipping of the two pieces 1,2 is done.

To perform the unclipping of the two pieces 1,2, one proceeds asfollows.

First of all, the lower piece 1 of the cassette is placed on top of thetool 5 facing the pins 50.

One inserts into each hole 13 a pin 50 of sufficient length to reach thefoot 21 in the position of its opening 210 clipped about a protrusion110 (FIG. 8). Thus, an upward thrusting force on the pins 50 lodged inthe holes 13 generates a lateral thrusting force on the feet 21 whichthen become unhooked from their corresponding protrusion 110, whichdissociates the two pieces 1, 2 (FIG. 9).

Advantageously, all the pins 50 are secured to a tool 5 as shown inFIGS. 6 to 9, which likewise comprises rigid feet 51 spaced apart fromeach other to allow a seating of the cylindrical body of the lower piece1. In other words, these rigid feet 51 serve as a guide to facilitatethe simultaneous thrusting of the pins 50 against the feet 21.

Alternatively, the feet can be situated on the lower piece and the holeson the upper piece, without leaving the scope of the invention.

As for the filter, this is supported by a filter holder. In theassembled configuration of the two pieces 1, 2, the filter holder 3 isheld squeezed between the two shoulders 14, 24 each produced on aninternal periphery of one of the two pieces 1, 2.

Advantageously, the filter holder 3 is chosen from an elasticallydeformable material and it then plays a supplemental role of a gasketbetween the lower 1 and upper 2 pieces of the cassette. In other words,it is advantageously possible to provide a filter holder 3 with a lesserhardness than the materials of pieces 1 and 2 of the cassette, so as tobe flattened against the opposite shoulders 14, 24, by pressure duringthe clipping process. As the filter holder 3 has the role of being amechanical support for the filter, it can have an overall annularconformation or be made from a single massive piece traversed by aplurality of holes emptying via straight channels in the thickness ofthe piece, this plurality of holes then forming the filter proper.

In any case, one will make sure that it generates the minimum of headlosses in the area of the aspiration.

According to one variant, the pieces 1, 2 of the cassette each comprisea notch 12, 22 running straight through the annular rim. The filterholder 3 comprises a tongue 4 that is complementary to the notches 12,22 and on which an identification element of the filter can be produced,so that in the assembled configuration of the pieces and in theconfiguration of the cassette secured to the apparatus theidentification element is in contact with the outer environment.

As illustrated in FIGS. 4A and 5, one can also provide an identificationelement of the filter composed of a radiofrequency identification (RFID)tag 4′ which is seated in the lower piece 1 of the cassette. Thesecuring of the RFID tag 4′ can be done advantageously by clipping inholding feet 16 provided for this purpose in a portion of the lowerpiece 1 constituting a seat which is physically protected against theoutside. This variant has the advantage of preserving an identificationon the filter itself, and allowing the filter to be subjected toanalyses which might alter the electronic circuit of the RFID tag 4′.Specifically, by seating a RFID tag 4′ in the piece 1 of the cassette,there are no longer any electronics integrated directly in the filterand filter holder 3, and thus an analysis undergone by the filter doesnot disrupt the electronic circuit of the tag. This likewise has theadvantage of allowing the RFID chip to be brought closer to the samplingapparatus and thus of reducing the transmission power of its antenna.

Depending on the needs, one can utilize in cumulative or alternativemanner an identification element 4 and/or an identification tag 4′. Forexample, one may use a number and/or letter code 4 visible to the nakedeye of a person from the outside and a tag 4′ seated in the lower piece1. One can also use only a number and/or letter code 4 or only a RFIDtag 4′.

To further improve the mutual assembly of the two pieces 1 and 2, onecan provide on each of them an annular rim 15, 25 in order to provide,in addition to the clipping, a mutual abutment surface between thepieces in their assembled position.

Advantageously, as illustrated in FIG. 4, a device to reduce theaspiration noise 7 is secured to the upper piece 2, as is described andclaimed in the patent application filed today by the applicant andentitled “Device for sampling and transporting of nano-objects containedin aerosols, with a cassette with a module suited to reducing thesuction noise during the sampling”.

Other variants and improvements can be made without thereby leaving thescope of the invention.

The invention is not limited to the examples just described; inparticular, one can combine the features of the examples illustrated inthe context of variants which have not been illustrated.

The invention claimed is:
 1. An assembly for sampling and transportingof nano-objects present in an aerosol for analysis, comprising: a devicecomprising: a porous sampling filter configured to trap nano-objects insuspension in the aerosol, a cassette composed of a first piece and asecond piece provided with means for holding the filter, the first andsecond pieces, in an assembled configuration, defining a cavity in whichthe filter is held, wherein: the first piece comprises at least oneelastically deformable foot extending from the first piece andcomprising an opening, and the second piece comprises at least onechannel configured to receive the at least one elastically deformablefoot, and a protrusion extending radially from the at least one channeland configured to engage the opening of the deformable foot when thefirst and second pieces are in the assembled configuration, and at leastone gasket configured to produce tightness between the cavity and anenvironment external to the cavity; a sampling apparatus comprisingmeans of aspiration and a seat defining a seat opening for receiving thecassette, wherein: the cassette is secured in the seat opening in aremovable manner when in the assembled configuration to accomplishsampling of contaminants by the means of aspiration, and when in theassembled configuration and when the cassette is secured in the seatopening, the at least one elastically deformable foot extends at leastpartly in seat opening and the seat prevents disengagement of theopening of the at least one elastically deformable foot from theprotrusion of the at least one channel.
 2. The assembly for sampling andtransporting as claimed in claim 1, wherein the means for holding thefilter comprises two shoulders, one shoulder disposed on an internalperiphery of the first piece and another shoulder disposed on aninternal periphery of the second piece, the device comprising a filterholder held by squeezing between the two shoulders.
 3. The assembly forsampling and transporting as claimed in claim 1, wherein at least one ofthe first piece and the second piece comprises a notch running straightthrough an annular rim, a filter holder comprising a tongue that iscomplementary to the notch and to which an identification element of thefilter is secured, such that in the assembled configuration of the firstand second pieces and in the configuration of the cassette secured inthe seat opening, the identification element is in contact with theexternal environment.
 4. The assembly for sampling and transporting asclaimed in claim 1, wherein the filter comprises an identificationelement comprising at least one radiofrequency ID tag (RFID), the atleast one RFID tag being lodged in the first piece and/or in the secondpiece.
 5. The assembly for sampling and transporting as claimed in claim1, wherein the at least one channel comprises a number n of the at leastone channel and a corresponding number of the at least one elasticallydeformable foot, wherein the number n of the at least one channel andcorresponding number of the at least one elastically deformable foot arearranged on the second piece and first piece, respectively, and spacedapart by an angular position equal to 2π/n.
 6. The assembly for samplingand transporting as claimed in claim 1, wherein the sampling apparatuscomprises means for commanding stoppage of the means of aspiration inresponse to removal of the cassette during a sampling process.
 7. Theassembly for sampling and transporting as claimed in claim 6, whereinthe sampling apparatus comprises visual and/or audio feedback generatedin response to removal of the cassette during a sampling process.